Projection exposure system with temperature control circuit

Abstract

The invention relates to a projection exposure system (1) for photolithography for imaging a mask (30) illuminated by an illumination system (10) onto a substrate (35) using a projection system (20), wherein at least one component (25) of the projection exposure system (1) is temperature-controlled via an active temperature control system (200) of the projection exposure system (1), the temperature control system (200) comprising at least one fluid line for conveying a temperature control medium, which is guided by at least one retaining element on a component (25) of the projection exposure system (1). At least one retaining element comprises a first part arranged on the component (25) of the projection exposure system (1) and a second part arranged on the fluid line, wherein the two parts of the retaining element are designed such that they are spaced apart from each other by magnetic levitation and are without mechanical contact.

Description

[0001] The invention relates to a projection exposure system for photolithography for imaging a mask illuminated by an illumination system onto a substrate using a projection system, wherein the projection exposure system has a temperature control circuit.

[0002] Photolithography is used to manufacture microstructured components, such as integrated circuits. The projection exposure system used for this purpose comprises an illumination system and a projection system. The image of a mask (also called a reticle) illuminated by the illumination system is projected in a reduced size onto a substrate coated with a light-sensitive layer and arranged in the image plane of the projection system, for example, a silicon wafer, by means of the projection system in order to transfer the mask structure to the light-sensitive coating of the substrate.

[0003] Both in illumination systems and in projection systems, in particular in projection exposure systems designed for the EUV range, i.e. for exposure wavelengths from 5 nm to 30 nm, several optical elements, in particular mirrors, are usually provided in order to achieve the desired image of the mask onto the substrate. Due to the required accuracy, it must be ensured, particularly in projection systems, that the position of the individual optical elements in relation to one another and to the mask and the substrate changes only within extremely small tolerances - if at all - during operation of the projection exposure system. Furthermore, the shape of the optical elements, in particular the mirror surfaces, must not change or must change only within a predetermined framework. Any change in the position and / or shape of one or more optical elements can lead to a reduction in the imaging quality of the projection system.

[0004] Corresponding changes in the position and / or shape of one or more optical elements can occur due to heat input into the optical elements or into the structure supporting the optical elements. Such heat input inevitably occurs, for example, due to the absorption of illumination radiation by the optical elements, the absorption of interfering radiation, particularly in the infrared range, and the heat loss from electrical components in the projection system. Electric actuators are known to compensate for changes in the position of the optical elements to a certain extent, but these actuators themselves also emit heat.In order to avoid or at least minimize the change in the shape of the optical elements starting from a desired shape and to dissipate heat introduced into the projection exposure apparatus, in particular its projection system, it is known to provide at least some of the optical elements and / or other components of the projection exposure apparatus and in particular of the projection system with fluid channels for the passage of a temperature control liquid - in particular demineralized water.

[0005] Even if the temperature of the individual components can be effectively regulated by passing a temperature control fluid through parts of the projection exposure system, so that changes in the position and / or shape of one or more optical elements due to heat input can be reduced or even completely avoided, it has been shown that passing temperature control fluid through the fluid channels provided for this purpose introduces vibrations into the components of the projection exposure system, which can lead to a reduction in image quality, particularly if they occur in the projection system.

[0006] Two effects are responsible for these vibrations introduced by the temperature control fluid: flow-induced vibrations (FIV), which result from the interaction of a turbulent flow with the wall of the flow channel, and waterline acoustics (WLA), in which vibrations of mechanical machines, such as a circulation pump, propagate through the temperature control fluid along the pipe in a similar way to sound in the air.

[0007] Even if it may be possible to reduce the overall vibrations introduced into the projection exposure system due to the passage of temperature control fluid by appropriately selecting the cross-section and other design of the fluid channels, the resulting vibrations can still reduce the image quality of a projection exposure system beyond a permissible level.

[0008] Some of these vibrations are also introduced at points in the components of the projection exposure system where the temperature control fluid is merely supplied or removed, without the components actually being temperature-controlled. The supply and discharge lines for the temperature control fluid required for this purpose are routed along the various components of the projection exposure system and attached to them at specific points using brackets. Any vibrations occurring in the lines held by these brackets are transmitted via these brackets to the component on which the bracket is located. The vibration introduced into a component via such a bracket can lead to unacceptable vibration of the component as a whole.

[0009] The object of the present invention is to provide a projection exposure system in which this problem no longer occurs or only occurs to a lesser extent.

[0010] This object is achieved by a projection exposure system according to claim 1. Advantageous further developments are the subject of the dependent claims.

[0011] Accordingly, the invention relates to a projection exposure system for photolithography for imaging a mask illuminated by an illumination system onto a substrate with the aid of a projection system, wherein at least one component of the projection exposure system is temperature-controlled via an active temperature control system of the projection exposure system, wherein the temperature control system has at least one fluid line for conducting a temperature control medium, which is guided by at least one holding element on a component of the projection exposure system, wherein at least one holding element comprises a first part arranged on the component of the projection exposure system and a second part arranged on the fluid line, wherein the two parts of the holding element are designed such that they are spaced apart from one another by magnetic levitation and are without mechanical contact.

[0012] The invention recognizes that for routing a fluid line within a projection exposure system, it is often sufficient to restrict the fluid line in the area of ​​a component in only one degree of freedom to ensure its desired path. Furthermore, the invention recognizes that the transmission of vibrations occurring in the fluid line into the component can be significantly reduced if the degrees of freedom not specified for routing the fluid line remain as free and unrestricted as possible.

[0013] To achieve this, the invention provides for the use of magnetic levitation in at least one holding element of a projection exposure system, in which - depending on the design - only one translational degree of freedom of the fluid line is necessarily restricted with respect to the component, while the other degrees of freedom can remain largely unhindered - i.e. "unrestricted". Thus, magnetic levitation necessarily only restricts the degree of freedom in the distance direction between the two parts of the holding element, while all other degrees of freedom - with a suitable design of the holding element - can basically remain free. Of course, if required, it is also possible to restrict further degrees of freedom of the fluid line with respect to the components on the holding element by means of alternative designs of the holding element and in particular of the elements relevant for magnetic levitation.

[0014] If a degree of freedom is unrestricted, a vibration or oscillation of one part of the support element in the direction of this degree of freedom is not transmitted to the other part of the support element. Therefore, if vibrations occur in a fluid line in the direction of an unrestricted degree of freedom, this vibration is not transmitted from the part of the support element arranged on the fluid line to the part of the support element arranged on a component of the projection exposure system or to this component.

[0015] Magnetic levitation also prevents any material connection between the two parts of the support element. Consequently, no solid-state heat transfer can occur between the two parts of the support element.

[0016] It is preferred if one of the two parts of the holding element is at least partially diamagnetic. By appropriately enhancing the properties of one part, it is possible to achieve the desired magnetic levitation through an at least partially permanent-magnetic design (e.g., through a suitable arrangement of a permanent magnet or suitable magnetization), which requires no external energy supply and also requires no active control.

[0017] Preferably, one part of the holding element is designed to generate a controllable magnetic field, with a control loop being provided to keep the distance between the two parts of the holding element constant. An electromagnet can be provided to generate the magnetic field, so that the magnetic field can be controlled via the current flow through the electromagnet. One or more sensors can be provided for control via the control loop, e.g. a sensor for determining the distance between the two parts of the holding element. The other part of the holding element can be diamagnetic, but this is not mandatory: Due to the provided control loop, it may be sufficient if the other part is merely ferromagnetic.

[0018] It is also possible for one part of the holding element to be designed to generate a high-frequency alternating magnetic field. In this case, an electrical conductor can be provided in the other part, in which eddy currents are induced due to its positioning in the alternating field, which ultimately imparts properties comparable to diamagnetism. Besides the control required to generate the high-frequency alternating field, further regulation is not absolutely necessary, since the magnetic levitation achieved in this way is essentially self-regulating.

[0019] Particularly when electromagnets are used for magnetic levitation, the part of the holding element designed to generate a controllable magnetic field and / or a high-frequency alternating magnetic field can be attached to the fluid line. The heat that regularly arises in an electromagnet due to electrical resistance can thus be directly dissipated via the fluid line attached to the part of the holding element. Supply lines, etc., for the electromagnet and any control circuit can also be easily routed along the fluid line. Alternatively, and generally preferred, however, the part of the holding element designed to generate a controllable magnetic field and / or a high-frequency alternating magnetic field is arranged on a component of the projection exposure system, along which the supply lines, etc., can also regularly be routed.Any heat transferred from the part of the holding element in question to the component must then be taken into account when designing the component and its cooling.

[0020] Particularly if no electrically operated part of the retaining element is arranged on the fluid line, it is also possible to implement the part of the retaining element to be arranged there as an integral part of the fluid line. If the fluid line itself is made of a suitable material, the retaining element can also be formed exclusively by the wall of the fluid line or parts thereof, so that no modification of the fluid line is required to create the relevant part of the retaining element.

[0021] The invention will now be described by way of example using advantageous embodiments with reference to the accompanying drawings. They show: Fig. 1: a schematic representation of a projection exposure system for photolithography; Fig. 2: a detailed section of the Fig. 1; Fig. 3a-c: schematic representations of possible designs of the holding element from Fig. 1 and Fig. 2.

[0022] In Fig. Figure 1 shows a projection exposure system 1 for photolithography as an example of a system for semiconductor technology in a schematic meridional section. The projection exposure system 1 comprises an illumination system 10 and a projection system 20.

[0023] With the aid of the illumination system 10, an object field 11 is illuminated in an object plane or reticle plane 12. The illumination system 10 comprises an exposure radiation source 13, which, in the illustrated embodiment, emits illumination radiation at least comprising useful light in the EUV range, i.e., in particular, with a wavelength between 5 nm and 30 nm. The exposure radiation source 13 can be a plasma source, for example an LPP source (laser produced plasma) or a DPP source (gas discharge produced plasma). It can also be a synchrotron-based radiation source. The exposure radiation source 13 can also be a free-electron laser (FEL).

[0024] The illumination radiation emanating from the exposure radiation source 13 is first focused in a collector 14. The collector 14 can be a collector with one or more ellipsoidal and / or hyperboloidal reflection surfaces. The at least one reflection surface of the collector 14 can be exposed to the illumination radiation at grazing incidence (GI), i.e., at angles of incidence greater than 45°, or at normal incidence (NI), i.e., at angles of incidence less than 45°. The collector 14 can be structured and / or coated, on the one hand, to optimize its reflectivity for the useful radiation and, on the other hand, to suppress stray light.

[0025] After the collector 14, the illumination radiation propagates through an intermediate focus in an intermediate focal plane 15. If the illumination system 10 is constructed in a modular design, the intermediate focal plane 15 can generally be used for the - also structural - separation of the illumination system 10 into a radiation source module, comprising the exposure radiation source 13 and the collector 14, and the illumination optics 16 described below. With such a separation, the radiation source module and illumination optics 16 then together form a modular illumination system 10.

[0026] The illumination optics 16 comprises a deflecting mirror 17. The deflecting mirror 17 can be a flat deflecting mirror or, alternatively, a mirror with a beam-influencing effect beyond the pure deflection effect. Alternatively or additionally, the deflecting mirror 17 can be designed as a spectral filter that separates a useful light wavelength of the illumination radiation from stray light of a different wavelength.

[0027] The deflecting mirror 17 deflects the radiation originating from the exposure radiation source 13 onto a first facet mirror 18. If the first facet mirror 18 is arranged—as in the present case—in a plane of the illumination optics 16 that is optically conjugated to the reticle plane 12 as a field plane, it is also referred to as a field facet mirror.

[0028] The first facet mirror 18 comprises a plurality of micromirrors 18', each of which can be individually pivoted about two mutually perpendicular axes, for the controllable formation of facets. Each micromirror 18' is preferably equipped with an orientation sensor (not shown) for determining the orientation of the micromirror 18'. The first facet mirror 18 is thus a microelectromechanical system (MEMS system), as described, for example, in DE 10 2008 009 600 A1.

[0029] In the beam path of the illumination optics 16, a second facet mirror 19 is arranged downstream of the first facet mirror 18, resulting in a double-faceted system whose basic principle is also referred to as a honeycomb condenser (fly's eye integrator). If the second facet mirror 19 is arranged in a pupil plane of the illumination optics 16—as in the illustrated embodiment—it is also referred to as a pupil facet mirror. However, the second facet mirror 19 can also be arranged at a distance from a pupil plane of the illumination optics 16, whereby the combination of the first and second facet mirrors 18, 19 results in a specular reflector, as described, for example, in US 2006 / 0132747 A1, EP 1 614 008 B1, and US 6,573,978.

[0030] The second facet mirror 19 does not necessarily have to be constructed from pivotable micromirrors, but can instead comprise individual facets formed from one or a manageable number of mirrors that are significantly larger than micromirrors, which are either fixed or can only be tilted between two defined end positions. However, as shown, it is also possible to provide the second facet mirror 19 with a microelectromechanical system comprising a plurality of micromirrors 19' that can each be individually pivoted about two mutually perpendicular axes, each preferably comprising an orientation sensor.

[0031] With the help of the second facet mirror 19, the individual facets of the first facet mirror 18 are imaged into the object field 11, which is usually only an approximate image. The second facet mirror 19 can be the last beam-forming mirror or even the last mirror for the illumination radiation in the beam path before the object field 11.

[0032] Each facet of the second facet mirror 19 is assigned to exactly one of the facets of the first facet mirror 18 to form an illumination channel for illuminating the object field 11. This can, in particular, result in illumination according to the Köhler principle.

[0033] The facets of the first facet mirror 18 are each imaged by an associated facet of the second facet mirror 19, superimposed on one another, to illuminate the object field 11. The illumination of the object field 11 is as homogeneous as possible. It preferably has a uniformity error of less than 2%. Field uniformity can be achieved by superimposing different illumination channels.

[0034] By selecting the illumination channels ultimately used, which is easily possible by appropriately adjusting the micromirrors 18' of the first facet mirror 18, the intensity distribution in the entrance pupil of the projection system 20 described below can also be adjusted. This intensity distribution is also referred to as the illumination setting. It may also be advantageous not to arrange the second facet mirror 19 exactly in a plane that is optically conjugated to a pupil plane of the projection system 20. In particular, the pupil facet mirror 19 can be arranged tilted relative to a pupil plane of the projection system 20, as described, for example, in DE 10 2017 220 586 A1.

[0035] In the Fig. However, in the arrangement of the components of the illumination optics 16 shown in Figure 1, the second facet mirror 19 is arranged on a surface conjugated to the entrance pupil of the projection system 20. Deflecting mirror 17 and the two facet mirrors 18, 19 are tilted both relative to the object plane 12 and relative to each other.

[0036] In an alternative, not-shown embodiment of the illumination optics 16, a transmission optics comprising one or more mirrors can be provided in the beam path between the second facet mirror 19 and the object field 11. The transmission optics can, in particular, comprise one or two mirrors for normal incidence (NI mirrors, normal incidence mirrors) and / or one or two mirrors for grazing incidence (GI mirrors, grazing incidence mirrors). With an additional transmission optics, different positions of the entrance pupil for the tangential and sagittal beam path of the projection system 20 described below can be taken into account.

[0037] Alternatively, it is possible that the Fig. 1 is dispensed with, for which purpose the facet mirrors 18, 19 are then to be suitably arranged opposite the radiation source 13 and the collector 14.

[0038] With the help of the projection system 20, the object field 11 in the reticle plane 12 is transferred to the image field 21 in the image plane 22.

[0039] The projection system 20 comprises a plurality of mirrors M i , which are numbered according to their arrangement in the beam path of the projection exposure system 1.

[0040] In the Fig. In the example shown in Figure 1, the projection system 20 comprises six mirrors M1 to M6. Alternatives with four, eight, ten, twelve or a different number of mirrors M i are also possible. The penultimate mirror M3 and the last mirror M6 each have a passage opening for the illumination radiation, which makes the illustrated projection system 20 a double-obscured optic. The projection system 20 has an image-side numerical aperture that is greater than 0.3 and can also be greater than 0.6, for example, 0.7 or 0.75.

[0041] The reflection surfaces of the mirrors M i can be designed as freeform surfaces without a rotational symmetry axis. Alternatively, the reflection surfaces of the mirrors M i but can also be designed as aspherical surfaces with exactly one axis of rotational symmetry of the reflection surface shape. The mirrors M i Like the mirrors of the illumination optics 16, they can have highly reflective coatings for the illumination radiation. These reflective coatings can be designed as multilayer coatings, in particular with alternating layers of molybdenum and silicon.

[0042] The projection system 20 has a large object-image offset in the y-direction between a y-coordinate of a center of the object field 11 and a y-coordinate of the center of the image field 21. This object-image offset in the y-direction can be approximately as large as a z-distance between the object plane 12 and the image plane 22.

[0043] The projection system 20 can in particular be anamorphic, ie it has in particular different image scales β x , β y in the x- and y-direction. The two magnifications β x , β y of the projection system 20 are preferably at (β x , β y ) = (+ / - 0.25, / +- 0.125). A magnification ratio β of 0.25 corresponds to a reduction in the ratio 4:1, while a magnification ratio β of 0.125 results in a reduction in the ratio 8:1. A positive sign for the magnification ratio β means an image without image inversion, a negative sign an image with image inversion.

[0044] Other magnifications are also possible, including identical and absolutely identical magnifications β x , β y in x and y directions are possible.

[0045] The number of intermediate image planes in the x- and y-directions in the beam path between the object field 11 and the image field 21 can be the same or different, depending on the design of the projection system 20. Examples of projection systems 20 with different numbers of such intermediate images in the x- and y-directions are known from US 2018 / 0074303 A1.

[0046] The projection system 20 can, in particular, have a homocentric entrance pupil. This can be accessible. But it can also be inaccessible.

[0047] A reticle 30 (also called a mask) arranged in the object field 11 is illuminated by the illumination system 10 and transferred to the image plane 21 by the projection system 20. The reticle 30 is held by a reticle holder 31. The reticle holder 31 can be displaced, in particular in a scanning direction, via a reticle displacement drive 32. In the illustrated embodiment, the scanning direction runs in the y-direction.

[0048] The reticle 30 can have an aspect ratio between 1:1 and 1:3, preferably between 1:1 and 1:2, more preferably 1:1 or 1:2. The reticle 30 can be substantially rectangular in shape and is preferably 5 to 7 inches (12.70 to 17.78 cm) long and wide, more preferably 6 inches (15.24 cm) long and wide. Alternatively, the reticle 30 can be 5 to 7 inches (12.70 to 17.78 cm) long and 10 to 14 inches (25.40 to 35.56 cm) wide, and is preferably 6 inches (15.24 cm) long and 12 inches (30.48 cm) wide.

[0049] A structure on the reticle 30 is imaged onto a light-sensitive layer of a wafer 35 arranged in the region of the image field 21 in the image plane 22. The wafer 35 is held by a wafer holder 36. The wafer holder 36 can be displaced, in particular along the y-direction, via a wafer displacement drive 37. The displacement of the reticle 30, on the one hand, via the reticle displacement drive 32, and the wafer 35, on the other hand, via the wafer displacement drive 37, can be synchronized with each other.

[0050] The Fig. The projection exposure apparatus 1 shown in Figure 1 or its projection system 20, the above description of which essentially reflects known prior art, is characterized in that a temperature control system 100 is provided with which various components of the projection system 20 can be kept at a desired temperature, whether changes in the position and / or shape of the mirrors 25, M1 to M6 are to be avoided or at least kept as small as possible.

[0051] In Fig. 1 and Fig. 2, which is merely an enlargement of part of the Fig. 1, for reasons of clarity, the temperature control system 100 is limited to the mirror M4 and is shown only very schematically. As indicated, among other things, by the additional inlets and outlets shown in dotted lines, the temperature control system 100 can also extend over further mirrors M1, M2, M3, M5 and / or M6 as well as other components not shown, such as in particular the support structure to which the mirrors M1 to M6 are attached. It is also possible for the temperature control system 100 to temperature-control components of the exposure system 10. However, the exposure system 10 can also have its own temperature control system.

[0052] The temperature control system 100 comprises fluid lines 101 for conveying a temperature control medium, a circulation pump 102 for conveying the temperature control medium through the fluid lines 101, and a controllable heat / cold source as an element 103 for actively controlling the temperature control medium. The fluid lines 101 are connected to a fluid channel 26 passing through the mirror M4 to be temperature-controlled, creating a closed temperature control circuit 105 for the temperature control medium.

[0053] The circulation pump 102 directs the temperature control medium, which can be controlled to a desired temperature using the active temperature control element 103, along or through various components, such as the mirror M4, where heat exchange occurs, so that the corresponding components approach the actively controlled temperature of the temperature control medium over time. This is widely known in the prior art.

[0054] The element 103 for actively controlling the temperature control medium can be provided as a heat pump with an electrically operated heating element, which is designed to supply or remove heat from the temperature control medium flowing through a heat exchanger.

[0055] To prevent vibrations of the circulation pump 102 and / or the active temperature control element 103 from being transmitted through the structure, the circulation pump 102 and / or the active temperature control element 103 are generally mechanically decoupled from the projection system 10 as much as possible and arranged away from it. For this reason, the circulation pump 102 and / or the active temperature control element 103 are generally arranged outside the evacuatable space provided for the optical elements of the projection exposure system 1. The system boundary between the evacuatable space and the area with ambient conditions is defined in Fig. 1 and Fig. 2 indicated by the dashed line 90.

[0056] In addition to the illustrated elements 101, 102, 103, the temperature control system 100 can also include other elements, such as controllable valves. If the temperature control system 100 is used to flow temperature control medium through several components of the projection exposure system 1 in different parallel temperature control circuits 105, valves can be used to individually adjust the flow rate in the individual temperature control circuits 105.

[0057] The fluid line 101 is attached to various components of the projection exposure system 1 by means of holding elements 200. In Fig. 1 and Fig. 2 shows only one holding element 200 as an example, the design of which will be discussed in more detail below.

[0058] All elements 101, 102, 103 of the temperature control system 100, as well as the fluid channels 26 through components of the projection exposure system 1, are designed to generate as few flow-induced vibrations as possible and to have line acoustics advantageously designed to dampen acoustic oscillations in the temperature control medium resulting from this or from other reasons. Despite such measures, flow-induced vibrations of the fluid lines 101 cannot usually be avoided, and these vibrations can also be transmitted to the components of the projection exposure system 1 via holding elements 200 for the fluid line 101 - in particular those according to the prior art. To prevent such vibrations from being introduced into components of the projection exposure system 1, at least at critical points, at least some of the holding elements 200 can be designed as shown by way of example in Fig. 1 and Fig. 2 is outlined.

[0059] The Fig. 1 and Fig. 2 outlined holding elements 200 comprises a first, on a - in the Fig. 1 and Fig. 2 - only indicated - component of the projection exposure system 1, and a second part 202, which is arranged on the fluid line 101. The two parts 201 and 202 of the holding element 200 are designed to be coordinated with one another in such a way that they are held at a predetermined distance from one another due to magnetic levitation.

[0060] Assuming that the part 201 of the holding element 200 arranged on the component of the projection exposure system 1 is essentially stationary, due to the magnetic levitation, initially only the degree of freedom of the other part 202 of the holding element 200 indicated by the double arrow 90 is restricted. All other degrees of freedom, however, are unrestricted. Consequently, only vibrations of the fluid line 101 in the direction 90 are transmitted via the holding element 200 to the components of the projection exposure system 1. Vibrations in the direction of other, deviating degrees of freedom are not transmitted. These must be absorbed otherwise if necessary, e.g., by rigid holding elements according to the prior art that are attached to less vibration-sensitive components of the projection exposure system (not shown).

[0061] In Fig. Figures 3a-c show various embodiments for the design of the holding element 200 in a schematic representation. In particular, the fluid line 101 is only partially shown.

[0062] In the embodiment according to Fig. 3a, a plate 204 made of diamagnetic material is arranged on the fluid line 101 as part 202 of the holding element 200. Part 201 of the holding element 200 arranged on the component of the projection system 1 is a permanent magnet 203, which creates a magnetic field in which the plate 204 magnetically levitates and thus maintains a constant distance from the fluid line 101 connected to it.

[0063] In the embodiment according to Fig. 3b, the part 201 arranged on the component of the projection system 1 is a ferromagnetic plate 205 that magnetically interacts with the electromagnet 206 provided as part 202 arranged on the fluid line 101 in order to achieve the desired magnetic levitation. The electromagnet 206 is supplied with electrical energy via supply lines 207 running along the fluid line 101. The actual current flow and thus the field generated by the electromagnet 206 is controlled by a control unit 208. The control unit 208 is designed to control the magnetic field depending on the distance to the component of the projection exposure system 1 determined via the sensor 209 so that the detected distance corresponds to a predetermined value. Any heat generated in the electromagnet 206 can be dissipated through direct contact with the fluid line 101 and the temperature control medium flowing therein.

[0064] It is also possible to assemble the two parts 201, 202 of the holding element 200 according to Fig. 3b. In this case, the electromagnet 206, the supply lines 207, the control unit 208, and the sensor 209 would be arranged on the component of the projection system 1, while only the ferromagnetic plate 205 would be arranged on the fluid line 101.

[0065] In the embodiment according to Fig. 3c, an electromagnet 210 is provided as part 201 of the holding element on the component of the projection exposure system 1, which is controlled via a control unit 211 such that the electromagnet 210 generates a high-frequency alternating magnetic field.

[0066] The fluid line 101 itself serves as part 202 of the holding element 200 arranged on the fluid line 101. In the illustrated region, the fluid line 101 is made of copper, which acts diamagnetically in the high-frequency alternating magnetic field generated by the electromagnet 210. This interaction, or further interactions resulting therefrom, results in the desired magnetic levitation. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2008 009 600 A1

[0028] US 2006 / 0132747 A1

[0029] EP 1 614 008 B1

[0029] US 6,573,978

[0029] DE 10 2017 220 586 A1

[0034] US 2018 / 0074303 A1

[0045]

Claims

[1] Projection exposure system (1) for photolithography for imaging a mask (30) illuminated by an illumination system (10) onto a substrate (35) with the aid of a projection system (20), wherein at least one component of the projection exposure system (1) is temperature-controlled via an active temperature control system (100) of the projection exposure system (1), wherein the temperature control system (100) has at least one fluid line (101) for conducting a temperature control medium, which fluid line is guided by at least one holding element (200) on a component of the projection exposure system (1), characterized byin that at least one holding element (200) comprises a first part (201) arranged on the component of the projection exposure system (1) and a second part (202) arranged on the fluid line (101), wherein the two parts (201, 202) of the holding element (200) are designed such that they are spaced apart from one another by magnetic levitation and are without mechanical contact. [2] Projection exposure apparatus according to claim 1, characterized by that one of the two parts (201, 202) of the holding element (200) is at least partially diamagnetic. [3] Projection exposure system according to one of the preceding claims, in particular according to claim 1, characterized by that a part (201, 202) of the holding element (200) is designed to generate a controllable magnetic field, wherein a control circuit is provided to keep the distance between the two parts (201, 202) of the holding element (200) constant. [4] Projection exposure system according to one of the preceding claims, in particular according to claim 1, characterized by that a part (201, 202) of the holding element (200) is designed to generate a high-frequency alternating magnetic field. [5] Projection exposure apparatus according to one of claims 3 or 4, characterized by that the part (201, 202) of the holding element (200) designed to generate a controllable magnetic field and / or a high-frequency alternating magnetic field is fastened to the fluid line (100). [6] Projection exposure system according to one of the preceding claims, in particular according to claim 4, characterized by that one part of the holding element is formed integrally with the fluid line (101) or is a part of the fluid line (101).

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